The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A typical multiple speed manual transmission having input and output shafts and multiple gear sets commonly includes longitudinal oil delivery bores in the shafts for delivery of lubricating oil received at one end of the bore to individual side bores opening into the longitudinal bore which direct the oil to the various gear sets. In manual transmissions oil splashed by a ring gear is commonly guided to the input shaft, main shaft needle bearings, and the gear synchronizers by an oil feeder which extends only partially into the oil delivery bore. At higher vehicle speeds such as above 80 Km per hour, i.e., when the input shaft is rotating at or above approximately 2500 rpm, a centrifugal force is created by the rotating input shaft that imparts back pressure to incoming fluid (transmission oil) entering the longitudinal bore. The centrifugal force can inhibit or prevent oil from reaching the side bores located proximate to an end of the shaft. This often results in limited, very negligible, or in some circumstances and rotational speeds no oil being delivered to the gear sets positioned proximate the last or end side bores of the shafts.
In known manual transmissions oil feeders are arranged generally in two different locations. In a first type, the oil feeder is located at a clutch side such that incoming oil to the transmission is dispersed primarily to lower speed gears such as gear 1 and gear 2. At higher shaft rotational speeds the synchronizers for the higher speed gears receive less oil, which is undesirable. In other known transmissions the oil feeder is located at a transmission side. In these transmissions incoming transmission oil is dispersed primarily to higher speed gears such as gear 5 and gear 6. At higher shaft rotational speeds the synchronizers for the lower speed gears will receive less oil, which is also undesirable.
While current transmissions achieve their intended purpose, the need for new and improved transmission configurations which exhibit improved performance, especially from the standpoint of delivery of lubricating oil to all gear sets at all operating speeds of the transmission.